This invention relates to an electronic keyboard instrument, and more particularly to an electronic keyboard instrument which is adapted to make its tone approximate to a tone of an external signal.
Generally, an electronic keyboard instrument produces a musical note corresponding to electric signals from a speaker and has the property of obtaining various tones by freely shaping the waveform of the electrical signal. To this end, the electronic keyboard instrument is usually designed to produce sounds of tones approximate to those of musical instruments, such as a violin, a flute, an organ, a piano, a clarinet, a glockenspiel, etc. by changeover of a switch.
In the prior art, signals of respective scales selected by keyboard switches are applied to fixed filters for waveform shaping to obtain various tones. Accordingly, the fixed filters are each provided for each tone and selected by the player's switch changeover operation to play a tune in a desired tone.